1. Field of the Invention
The present invention relates to a display panel and a manufacturing method of the display panel.
2. Description of Related Art
Conventionally, a plasma display panel (PDP) has been configured by: disposing a pair of planar substrates to face each other with a discharge space interposed therebetween; partitioning the discharge space into a plurality of discharge cells by providing a curb-shaped or striped partition on an inner surface of one of substrates; and providing the partitioned portions with phosphor layers exemplarily of red, blue and green. The PDP displays images by selectively discharging inside the discharge cells for light emitting. As a method for forming the phosphor layer in the PDP, there has been know an ink-jet method, with which a phosphor material is injected to between the partitions using, for example, a nozzle (e.g. see Document: JP-A-2002-75216).
According to a manufacturing method of a plasma display panel (PDP) disclosed in Document, an address electrode is formed on a rear panel substrate, partitions are formed on the address electrode with a pitch of a predetermined value, and a phosphor layer is formed between the partitions. The phosphor layer according to the manufacturing method of the PDP is formed using an ink ejecting device that ejects phosphor ink. A plurality of nozzle bodies of the ink ejecting device, each of which includes a nozzle and a header, are fixed to a fixing table. A supply pipe for supplying the phosphor ink from a pressurizing supply unit is connected to the header while a nozzle-flow-rate controlling valve provided to the nozzle controls a flow rate of the phosphor ink ejected from the nozzle. In the manufacturing method of the PDP, the ejecting amount of the nozzle is measured before the phosphor ink is applied, and the flow rate of the nozzle is variably controlled per one scanning, thereby preventing a column variation.
However, according to the method in which the nozzle ejects the phosphor ink for forming the phosphor layer, an error in an opening dimension of the nozzle may cause a difference in the ejecting amount of the phosphor ink, which can lead to a difference in a thickness of the phosphor layer. When there is an error in the opening dimension of the nozzle, a difference as much as the fourth power of the error value of the nozzle opening is caused in the thickness of the phosphor layer.
Although such a conventional manufacturing method of a PDP as disclosed in the above Document may be used for solving such problems, the conventional manufacturing method of the above Document requires a detector for detecting the ejecting amount of the nozzle and a complex control program for controlling the flow rate of the nozzle by a controller, which leads to a complication of a configuration.
Another possible arrangement is to thin the phosphor layer so as to reduce variations of the thickness, thereby suppressing a column variation. However, since the thickness of the phosphor layer is generally specified by a panel standard for a display panel, a realization of the arrangement may be difficult.
Another possible arrangement is to provide a base layer by printing between the phosphor layer and the substrate and to form the phosphor layer on the base layer, thereby reducing the thickness dimension of the phosphor layer. However, when the base layer is printed, a variation can be caused in a thickness dispersion, which can lead to a luminance variation.